1. Field of the Invention
The present invention relates to a pedestrian protection apparatus for a vehicle, and in particular to an improved structure of the pedestrian protection apparatus for a vehicle installed at a lower part of a front section of the vehicle and arranged to sweep a leg portion of a pedestrian that has collided with or contacted a front face of the vehicle, thereby protecting the leg portion of the pedestrian.
2. Description of the Related Art
In vehicles such as automobiles, there are conventionally disposed, at a front face, a rear face, or side faces, of the vehicle, various types of protection apparatus which absorb impact energy generated upon a collision for protecting the vehicle body and passengers. In recent years, there is disposed, at the front face of the vehicle, an apparatus for protecting a pedestrian upon a collision or contact of the pedestrian with the front face of the vehicle.
As one type of the pedestrian protection apparatus, there is known a so-called leg-sweep apparatus which includes a plate member fixed at a lower part of the front section of a vehicle in a state of being arranged to extend in a frontward and backward direction of the vehicle. A front end portion of the plate member is arranged to come into contact with a leg portion of a pedestrian that is collided with the front face of a vehicle and sweep (scoop up) the leg portion of the pedestrian, thereby causing the pedestrian to fall down toward the vehicle. Thus, it is possible to advantageously limit a knee-bending angle in an abnormal direction upon the contact of the pedestrian with the vehicle, so that the occurrence of injuries such as a knee fracture can be minimized, thereby assuring protection and safety of the pedestrian. (See, JP-A-2004-203183, for example.)
The pedestrian protection apparatus (leg sweep apparatus) structured as above has an advantage in that the entire apparatus including the plate member can be easily integrally molded with an excellent formability by molding operation or the like using a synthetic resin material, for example. However, in an attempt to further improve the pedestrian protection apparatus, the inventors of the present invention examined the structure of the pedestrian protection apparatus having the foregoing features from various aspects and found that the known pedestrian protection apparatus has following drawbacks.
Specifically, in the above known pedestrian protection apparatus, the plate member is generally disposed at the lower part of the front section of the vehicle so as to extend continuously over the entire width of a vehicle width such that the plate covers the substantially entire surface of the lower part thereof. Thereby, the pedestrian protection function can be securely exhibited even if the pedestrian comes into contact with any part of the front face of the vehicle. Thus, in the plate member, there is formed an outlet hole penetrating therethrough in a plate thickness direction, so as to discharge a foreign substance such as water, mud, gravel or a pebble entered through a gap between the plate member and the vehicle (vehicle body) to the outside. Due to the mechanism, during traveling of the vehicle, a part of air flowing from a frontward to a rearward of the vehicle on an upper surface side of the plate member is released at a furious speed from the outlet hole to a lower surface side of the plate member in a vertically downward direction. It was found that this causes a problem of disturbing a horizontal airflow under the vehicle, and resulting in an increase of air resistance of the vehicle.
On the other hand, in conventional vehicles such as an automobile, there is generally disposed an undercover for covering an engine room or the like from an underside thereof. The undercover includes a cooling air outlet for releasing air taken into an engine room as a cooling air for a radiator, where the cooling air outlet is formed so as to penetrate through the plate in the thickness direction thereof. Such an undercover can also cause the problem of increasing an air resistance due to the mutual interference between air released from the cooling air outlet in the vertically downward direction and air flowing under the vehicle toward the rear of the vehicle during traveling of the vehicle under the state where the undercover is installed therein. Consequently, there has been proposed a technology in which a large opening portion open toward the rear of the vehicle is provided between a floor panel or the like and the undercover to release the air inside the engine room toward the rear of the vehicle therethrough, thereby preventing the disturbance of an air flowing under the vehicle (e.g. See JP-A-08-276867).
Then, it is conceivable that the technology for reducing the air resistance of the undercover can be applied to the known pedestrian protection apparatus for a vehicle having the foregoing internal problems, that is, the large opening portion open toward the rear of the vehicle can be provided between the plate member and an opposed member thereof, in addition to the outlet hole. The ordinary pedestrian protection apparatus, however, is installed at a more frontward position than a position of the radiator disposed in the front section of the vehicle. Thus, when the above technology is applied as it is, a large amount of cooling air is allowed to flow from the opening portion positioned more frontward than the radiator to the outside. This results in a new problem of deterioration of a cooling performance of the radiator due to a shortage in the ventilation amount of cooling air flowing toward the radiator.
Meanwhile, in the front section of the vehicle, when the plate member is disposed so as to extend astride the radiator in the frontward and backward direction of the vehicle and the outlet hole is formed in a portion of the plate member located immediately below the radiator or located more rearward in the vehicle than the radiator, the foregoing proposed technology can be applied to the pedestrian protection apparatus with a sufficient amount of ventilation to the radiator secured. However, then in turn, the force of air released downwardly from the outlet hole increases, which causes a concern about a more significant increase in the air resistance under the vehicle.